ULTRASTRUCTURE OF HUMAN SPERM USING X-RAY MICROSCOPY

X-ray microscopy (XSM) of human sperm provided surface detail from mot ile sperm, without the fixation and radiation damage associated with e lectron microscopy and at higher resolution than with light microscopy (LM). Vesicles of 0.7 to 5.0 mu m were found in the mid-piece region and could be either granular or clear. In addition, XM revealed smalle r vesicles at the head and tail regions. More vesicles were found usin g XM than LM. In part, this was attributed to its superior resolution. However, new vesicles were probably created during XM. Vesicles appea r to be areas where the plasmalemma has detached from the underlying c ytoplasm and expanded. Density gradient centrifugation did not provide a more robust population of sperm. However, prior fixation with gluta raldehyde reduced the incidence of vesicles in XM again, indicating so me formation ne novo. Cryopreserved sperm, which are known to be susce ptible to membrane damage, were not further affected by XM. (C) 1998 L ippincott Williams & Wilkins.